Exhalation valve structure for protective masks



Aug. 10, 1943. H. A. HUSTED 2,326,651

EXHALATION VALVE STRUCTURE FOR PROTECTIVE MASKS Filed Sept. 20, 1941 2 Sheets-Sheet l Ill/ll ////l '9 lNVENTOR HARRY A. HUSTED' ATTORNEW Aug. 10, 1943.

H. A. HUSTED EXHALATION VALVE STRUCTURE FOR PROTECTIVE MASKS '2 Sheets-Sheet 2 Filed Sept. 20, l941 FIG-6 FIG-5 FIG-7 INVENTOR HARRY A. HUSTED BY FIG-ll Patented Aug. 10, 1943 EXHALATION VALVE STRUCTURE FOR PROTECTIVE MASKS Rm, .4. Busted, Detroit, Mich, assignor to The Standard Products Company, Detroit, Mich, a corporation of Ohio Application September 20, 1941, Serial No. 411,614

4Claims.

The invention relates to respiratory devices, such as gas and like types of masks, and more particularly, to exhalation valves for devices of this nature. Such exhalation valves are usually conveniently positioned in that portion of the mask which, while in service, is arranged in general juxtaposition to the mouth and nose of the wearer, said portion being generally termed the face piece.

A serviceable gas mask must include suitable means for supplying a breathable atmosphere from a convenient portable source. It must also include suitable valve means for, permitting exhalation by the wearer, the exhalation valve being usually a one-way valve so as to prevent ingress of toxic vapors.

For convenientgeneral use, a gas mask may also include other elements, for instance some means, impermeable to gases, for the transmission of speech vibrations therethrough. Such latter means is shown, for example, in my copending application, Serial No. 389,129, filed April 18, 1941. The present application discloses and claims distinctly novel and improved exhalation valves applicable both to a face part such as is disclosed in the aforesaid copending application and also to respiratory devices in general.

As will be readily appreciated by anyone who has worn a respiratory device for any appreciable length of time, one of the principal objections to its use arises from the sense of discomfort experienced by the wearer, especially with respect to the action of exhalation. This is particularly true in the case of those of the civilian population who are aiilicted by bronchial, pulmonary, or cardiac diseases, or in the case of individuals, either civilian or military, who are m volved in strenuous activities which cause hurried or labored breathing, accompanied by physical fatigue. It is common knowledge in military circles that a company of soldiers required to do strenuous construction work, or to run uphill, or otherwisejntensify the usual physical pace, complain of breathing handicaps imposed by the use of the gas mask. It is common knowledge, also,

valves of prior respiratory devices have been so constructed and arranged, in order to have the valve members of such valves so tightly engage their seats to prevent ingress of toxic vapors that the physical effort required to move the valve members from their seats during exhalation was so fatiguing as to make such prior devices quite unsatisfactory. Furthermore those prior exhalation valves which were of the rubber diaphragm type were so distorted due to the tension arising from the mounting method as to produce permanent set or make them otherwise too insensitive for ease of exhalation. Moreover prior exhalation valves including those of the diaphragm type have been of more or less complicated character, expensive to manufacture and mount, and unsuitable for use as'a standard valve for all masks.

-The general object of the present invention is the provision of an exhalation valve for respiratory devices, such as gas masks and the like, said valve being of exceedingly simple form and construction, capable of being inexpensively manufactured to accurate dimensions in commercial production, and in which the valve member may be easily, quickly and conveniently attached to and removed from its support.

A more specific object of the present invention is the provision of an exhalation valve for respiratory devices of the rubber diaphragm type, the periphery of the diaphragm valve having suflicient contact with the valve seat to effectively prevent ingress of toxic vapors during inhalation but which can be so easily moved from its valve seat during exhalation as to avoid any fatigue or discomfort on the part of the wearer of the respiratory device.

Another specific object of the present invention is the provision of an exhalation valve having a valve member of disk-like form and of imperforate character, said valve member having a centrally disposed socket for enabling said member to be easily and quickly attached to and removed from its supporting stud, the mounting of said valve member being such that the rubber material of which it is made is not distorted or given a permanent seat which would otherwise result 'in a short life and faulty valve operation. Another specific object of the present invention is the provision of an exhalation valve of the character heretofore referred to, and in which the disk-like valve member and its supporting stud are so constructed and arranged as to insure the accurate mounting of the valve member under predetermined conditions.

Another object of the present invention is the provision of an exhalation valve which includes a disk-like valve member of rubber or like material and a support therefor which may be made of organic plastic material, said plastic support having the valve seat thereon, andcapable of being given a form and shape which enables it to be used with various types of respiratory devices, such as the so-called gas masks, oxygen masks, dust masks and the like.

Other objects and advantages will be apparent to those skilled in the art on a consideration of the following description of two embodiments of the invention, in conjunction with the attacheded drawings, in which Fig. 1 is a front elevation of a mask face part containing an exhalation valve;

Fig. 2 is a vertical sectional view thereof, with a part of the lower portion of the face part in elevation;

Fig. 3 is an enlarged fragmentary section on the line 3-4 of Fig. 1, with the periphery of the exhalation valve element in edge or line contact with the valve seat;

Fig. 4 is a view similar to Fig. 3 but showing the periphery of the valve element in surface contact with the valve seat, the relation of the parts during inhalation;

Fig. 5 is a view similar to Fig. 3 but showing the valve element unseated as a result of exhalation;

Fig. 6 is a front elevation of the lower portion of the face part, the perforate cap of the valve housing of such part being removed;

Fig. '7 is a detail vertical section, on the line 'I-l of Fig. 5;

Fig. 8 is a vertical section of the mask face part containing a somewhat modified exhalation valve, the portion of the mask in which said face part is mounted being broken away;

Fig. 9 is a rear view of the face part of Fig. 8 as seen from the interior;

Fig. 10 is a plan view illustrating one method of mounting the supporting stud for the valve member of either of the aforesaid exhalation valves; and

Fig. 11 is a section on the line l|-ll of Fig. 10.

Before the present invention is described in detail, it is to be understood that such invention is not limited to the details of construction and/or the specific arrangement of parts herein illustrated and/or described, as the invention obviously may take other forms. It also is to be understood that the phraseology or terminology herein employed is for the purpose of description and not of limitation.

For purposes of illustration, Figs. 1 to 7 inclusive of the drawings show a gas mask face piece generally designated by reference numeral II, and preferably fabricated from organic plastic material, such as cellulose acetate, by a pressure casting operation. The contours of the face piece generally, and of the structural elements of the exhalation valve now to be described, are so simple that, whether fabricated in several sections or integrally, the casting operation is a simple one.

The face piece here shown in 'Figs. 1 to 7 inclusive includes speech transmission means in a housing l2, said means not being described in detail herein since not an essential element of the present invention. The face piece is carried by a pliable face-enveloping member l3 in conventional manner, said face piece being shown only in fragmentary manner in Fig. 2.

The face part I l comprises an exhalation valve housing It, the purpose of which is to enclose, support and protect the exhalation valve now to be described. The open front of the housing It carries a foraminous cap l5 which, in the embodiment shown, consists of a domeshaped front portion having radially spaced annular members It supported by radial struts l1, said struts radiating from a central boss l8 and being integral with the annular members l6. While the cap may be attached to the housing in various ways, it is shown (see Fig. 3) as having a cylindrical skirt or flange I9 which is exteriorly threaded to fit a corresponding internal thread on the cylindrical wall of the housing I4. This cap protects the vitally important exhalation valve member from intentional or accidental impacts, the results of which might be of serious consequence to a wearer of the mask. As will be readily apparent from an examination of Figs. 1 and 3, the openings of the cap I5, especially the outer set of openings [5a, are of sufficient area to prevent any appreciable impedance to the outward flow of exhaled gases, and yet do not effect any material weakening of' the cap.

Located centrally within the valve chamber defined by the housing I4 is a. forwardly projecting stud or button 20 preferably having an enlarged head 2|. Said stud is supported on a spider 22 which is preferably formed integrally with the housing l4 and which is centrally perforated at 23 to receive and retain the shank 24 of the stud. While the stud may be formed integrally with the spider, the method of construction and assembly hereinafter described and shown in Figs. 10 and 11 is more suited to a uniform precision such as is desired, if not actually required, in a device of the character here involved.

In mounting the stud 20 in the spider aperture 23, the internal peripheral wall of said aperture is first coated with a suitable adhesive, such as acetone. A suitable spacing gage 25, of U form, is then placed with its leg members 26 straddling the aperture. The shank 24 of the separately formed stud 20 is then insorted in the aperture as far as said gage will permit, or in other words, until the stud head 2| comes in contact with the gage legs 25, and the stud is maintained in this position for a brief period until incipient hardening of the adhesive permits withdrawal of the gage. By this method, a high degree of accuracy and precision is obtained in the positioning of the stud head 2| relative to the spider 22, with a result to be.

soon described. If the stud 20 is cast integrally with the spider 22 of housing I4, the shank of said stud would give rise to certain additional problems of mold design, requiring lateral withdrawal of certain die inserts which define said shank, thereby leaving upon the shank so called parting lines or minor fiash projections which, even if not evident enough to require a trimming or machining operation, would have a tendency to impair the unstressed operation of the valve member 21 which is mounted on the stud 20 and which valve member is now to be described.

As here shown, said valve member is a onepiece, imperforate disk or diaphragm of rubber or like material and of inverted saucer-like form in cross section. Extending centrally through said disk or diaphragm 21 and projecting from opposite faces thereof is a tubular and some.- what thickened hub-like part 23, closed at its front end and defining a rearwardly opening recess or socket 23 for the reception of the stud 20. The forward end of said recess or socket is suitably enlarged to receive the head 2| of the stud 20, and as will be readilyunderstood, assembly of the valve disk or diaphragm 21 with its supporting stud 20 is readily effected by drawing thetubular hub of said disk or diaphragm over the projecting portion of said stud, with the consequent location of said stud in the recess or socket 29 of the valve member. As but shownin Figs. 3 to 5 inclusive, the reduced part of the valve member hub is of such length as to just contact the under surface of the stud head 2! inthe plane designated by the reference numeral 3|, and to just contact the spider 22, in the plane designated by the reference numeral 32.

A clearance space 33 (see Fig. 4) of minute dimension, in the order of one thousandth /1ooo") of an inch in sectional extent, preferably is provided in the valve socket or recess 29 around the stud 20, except in the contacting planes 3| and 32 heretofore referred to. Since these two contactcated that this present valve, while definitely leakproof in neutral position and during inhalation, may be opened at a considerably lower exhalation pressure thanprior valves, with comparable leakproof characteristics. For this reason, the present valve causes no feeling of discomfort and as a result, the wearer of a mask containing the present exhalation valve is not tempted to remove his mask, as has heretofore been done, even in the face of danger, by the wearers of masks utilizing prior exhalation valves. While the supporting stud for the valve member 21 is shown as carried by a spiderlike member 22, it may obviously be carried by a perforated plate, or by other supporting means which permits passage therethrough of exhaled gases.

Figs. 8 and 9 illustrate a face part 42, of a form particularly suitable foroxygen, dust and like masks, said face part containing an exhalation valve embodying a somewhat modified form of the present invention. As shown, said face part in- I cludes a valve housing generally similar to the mg areas 3| and 32 are of minor extent as compared with the total surface area of the valve 21, the major portion of the valve is maintained in an unstressed, floating condition, although positively positioned with respect to its seat 33 by the cooperating effect of the contacting surfaces 31-32. The aforesaid clearance spaces permit any slight displacement arising from flexure of the valve material as the valve member moves through its functional cycle in use thereof.

The operation of the valve is as follows, with special reference to Figs. 3, 4 and 5. Fig. 3 shows the normal position of the valve member 21, in idle condition, a circular line contact being maintained between the peripheral edge of the valve diaphragm and the valve seat 33 on the bottom face of the valve chamber 34. The accuracy of assembly heretofore described, and the generally floating suspension of the valv member 21 contribute to permit a most sensitive and stress-free contact of the periphery of the valve member with its seat 33, which obviously is essential in a satisfactory respiratory device. w

A slight inhalation eflort temporarily reduces the pressure on the inner valve member face which immediately brings about a planar contact of the valve member periphery with the valve seat 33, said valve seat having a conically inclined portion 35 designed to be engaged by a similarly inclined portion 38 of the ,valve diaphragm. This provides a sealing contact of substantial extent during inhalation, the relative position of the cooperating parts at this time being shown in Fig. 4.

Fig. 5 shows the position of the valve member during exhalation, the periphery of the valve member being lifted from its seat, as shown by reference numeral 31, to an extent determined by the energy of exhalation, but amply suflicient to allow egress of'the exhaled gases without any perceptible discomfort such as has been experione heretofore described and from which extends, rearwardly, a tubular portion 42a. Located within the valve chamber defined by said housing is a centrally disposed stud on which is mounted an exhalation valve member 43 which differs from the valve member 21 heretofore described only in thatthe peripheral portion of valve member 43 is of generally flat form, the valve seat 44, with which the valve member 43 has coplanar contact for sealing P poses, being .of like flat form.

Although the tubular portion 42a of this second face part 42 may be detachably secured to a mask member in any suitable manner and by any suitable means, I have shown it in this embodiment as being provided with a rear terminal flange 40, the plane of the flange being normal to the cylindrical ,axis of the tubular portion. There is thus provided, between the flange 40 and the flared front portion which constitutes the 'mask part 38 and the face part 42 to be easily,

quickly and conveniently assembled. It also permits ready substitution of a new face part in case the old one is damaged or the like.

I have further .shown, in Fig. 8, a stud construction differing somewhat from that shown in Figs. 1 to 7. The shank of the present stud is provided with a reduced end 45 to "seat in the bore 46 of the supporting spider 41, thereby providing a shoulder 48 disposed to contact the spider hub 49. In forming the stud the location of the shoulder 48 and the s'tudhead 50 are accurately predetermined to obtain, in the flnal valve assembly, a precision in the dimensional relation of the parts which is commensurate with that obtained with the spacing gage already described. In the present embodiment the spacing gage may be dispensed with since the stud is inserted in the central bore 46 of the spider until the shoulder abuts the spider. The gage of course may be used if it is desired to terminate the stud insertion somewhat short of actual shoulder contact such as described.

It is apparent from the drawings that the manner of mounting the valve member 43 on its supporting stud is similar to that already described in connection with the embodiment previously referred to. It also is to be understood tests on valves heretofore available have indithat the face part 42 of Figs. 8 and 9 may be constructed, if desired, with a valve seat of the contour of the valve seat 01' the face piece of Figs. 1 to '7 inclusive, for use with a valve member having the inverted saucer-like form of the valve member 11.

As previously indicated, the face parts H and 42, including the detachable caps thereof, are preferably fabricated from organic plastic material by pressure molding processes. The valve members or diaphragms 21 (Figs. 1 to 7) and 43 (Figs. 8 and 9) are preferably formed from rubber or rubberlike material, either natural rubber or synthetic rubber.

Other features and advantages of the present invention will occur to those skilled in the art to which it relates.

What I claim is:

1. An exhalation valve structure for a respiratory device such as a gas mask, said valve structure comprising a wall portion provided with an exhalation aperture, a resilient valve member of disk-like form normally engaging at its peripheral edge the said wall portion to normally seal said aperture, said valve member being imperforate and having a centrally located undercut socket, and a headed p oje member ried by said wall portion and seated in said socket for supporting said valve member, said headed projecting member being in contact with the valve member only throughout a minor portion of the interior surface area of said socket.

2. An exhalation valve structure for a respiratory device such as a gas mask, said valve structure com-prising a wall portion provided with an exhalation aperture, a valve member having a resilient, imperi'orate disk-like portion normally engaging at its periphery the said wall portion to thereby seal said aperture, said disk-like portion having a centrally located socket, and a. stud having a shank carried by and rigid with said wall portion, and having a head spaced from said wall portion and seated in said socket, said valve member having an annular flange below said disk-like portion and surrounding said stud between its head and said wall portion, said flange being of greater thickness than the Periphery of said disk-like portion.

3. An exhalation valve structure for a respiratory device such as a gas mask, said valve structure comprising a wall portion provided with an exhalation aperture, a valve member having a resilient, imperforate disk-Jike-portion normally engaging at its periphery the said wall portion to thereby seal said aperture, said disk-like portion having a centrally located socket,- and a stud having a shank carried by and rigid with said wall portion, and having a head spaced from said wall portion and seated in said socket, said valve member having an annular flange below said disk-like portion and surrounding said stud between its head and said wall portion, said disklike portion being spaced from the head of said stud, and said flange being in contact with said wall portion and the head of said stud.

4. An exhalation valve structure for a respiratory device such as a gas mask, said valve struc-' ture comprising a wall portion provided with an exhalation aperture, a valve member having a resilient, imperforate disk-like portion normally engaging at its periphery the said wall portion to thereby seal said aperture, said disk-like portion having a. centrally located socket, and a stud having a shank carried by and rigid with said wall portion, and having a head spaced from said wall portion and seated in said socket, said valve member having an annular flange below said disk-like portion and surrounding said stud between its head and said wall portion, said disk-like portion being spacedfrom the head of said stud, and said flange being in contact with said wall portion and the head of said stud but being free of contact with the shank of said stud.

HARRY, A. HUS'I'ED. 

